Daryl Clark only signed a 5 year deal in October 2011, he's young, a Castleford lad and of course they'll want him for their future so I can't see it happening. They have let Shenton (at the time, but now going back of course), Westerman, Eden, Arundell all go, they need to hold onto talent if they are to progress.
From what I've seen he's a great young talent and his stats back that up, but so is our young hooker Brad Dwyer.